Very small, black flies on plants and clones, how do i get rid of them? Bug Bomb?

My babies are halfway through flowering but i am noticing a lot of very small flies, they dont seem to be doing any harm.

I am willing to ride it out this time and not do anything, but once it has finished i do not want it to happen again on the next one.

What can i do when the room is free of plants to kill any left over nasties?

I have heard of a 'bug bomb,' has anybody had results with this or a similar product?

What causes these flies? the intake was un-filtered to begin with but now i have a tight on the end which stops anything coming in, could that be what caused the flies?

I am also seeing a few tiny flies flying around my clones so can someone suggest a product i can submerge them in before they go in the main room to get rid of any potential nasties?

All feedback is welcomed, cheers.

Hey man! I think what you are talking about are fungus gnats, and though you think there will be no harm, they land on leaves and leave behind a shiny little streak of body juices; these juices block the light and kill the chlorophyll beneath them where you'll see the leaves dying. There is a product by Safer called "End All". It kills eggs and bugs both. Hope this helps!

konk bomb will contain the problem and is probably the only thing you would want to use at this stage of flower. Neem will ruin the bud and is one of the primary ingerdients in end all. The bomb will only kill what is alive, the eggs will hatch again in 3 days... at this stage of the game all you can do is control the problem. Once you cut it down completely disinfect your grow room from top to bottom to be sure the biaaches are gone (I use diluted h202 in a sprayer). If you are cloning off of a mother plant start using end all or something similar every 3 days on the mother until they are gone.

Thank you both, that sounds like good advice.

Spray on the soil and the plant. Just make sure the soil is wet before applying